Method for forming a prefabricated truss deck



Feb. 21, 1967 w. w. FRANTZ 3,305,612

METHOD FOR FORMING A PREF'ABRICATED TRUSS DECK Filed June 5. 1964 5Sheets-Sheet 2 BY W M,.

Feb. 21, 1967 w. w. FRANTZ 3,305,612

METHOD FOR FORMING A PREFABRICATED TRUSS DECK Filed June 5, 1964 5Sheets-Sheet :5

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IIIHIIHIIIIIIIIIIIHHHI H H l' 3} 0/ 36 17 ml 96 i3} r H m i /0/ 70 l.c." H x\.' U H K68 R70 68 as United States Patent 3,305,612 METHOD FORFORMING A PREFABRICATED TRUSS DECK Woodrow W. Frantz, Nazareth, Pa.,assignor, by direct and mesne assignments, to Conodec Inc., Easton, Pa.,a

corporation of Pennsylvania Filed June 5, 1964, Sen. No. 372,796 4Claims. (Cl. 264-69) This invention relates to a method for producing aprefabricated truss deck.

Prefabrication of structural components for a building has becomewidespread. It has been found that structural components can be moreeconomically shop fabricated and assembled at the construction site.

This invention relates to the shop fabrication of a floor or roofcomponent. In particular, this invention deals with the fabrication of afloor or roof component comprising a pair of substantially parallel openweb steel joists embedded within a precast concrete slab.

Accordingly, it is an object of this invention to provide a method forforming a prefabricated truss deck.

A more specific object of this invention is to provide a method forforming a prefabricated truss deck in a more economical manner.

Yet another object of this invention is to provide a method for forminga plurality of prefabricated truss decks in a single continuousoperation.

Another object of this invention is to provide a method for forming aplurality of prefabricated truss decks in a single continuous operationwhich can easily be joined to each other at a construction site forforming a roof or floor.

Other objects will appear from the disclosure which follows hereinafter.

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIGURE 1 is a top plan view of a portion of the apparatus used incarrying out the method of the instant invention and illustrates acasting bed and a hopper mounted thereon for selectively dispensing acementitious mixture into the casting bed.

FIGURE 2 is an end view in elevation of the apparatus illustrated inFIGURE 1 as seen substantially along the plane indicated by the line 2-2of FIGURE 1.

FIGURE 3 is a fragmentary cross sectional view taken substantially alongthe plane indicated by the line 33 of FIGURE 2.

FIGURE 4 is an end view in elevation of the structure illustrated inFIGURE 3 as seen from the plane indicated by the line 4-4 of FIGURE 3.

FIGURE 5 is a fragmentary perspective view of one end of the casting bedillustrated in FIGURE 1.

FIGURE 6 is a perspective view of a preassembled truss structurecomprising a portion of the end product formed by the method andapparatus of the instant invention.

FIGURE 7 is an enlarged fragmentary plan view of one end of the trussillustrated in FIGURE 6.

FIGURE 8 is a fragmentary cross sectional view taken substantially alongthe plane indicated by the line 8-8 of FIGURE 7 and also showing inphantom the manner in which the truss is adapted to be located relativeto the casting bed in accordance with the method of the instantinvention.

FIGURE 9 is a fragmentary enlarged plan view of the other end of thetruss illustrated in FIGURE 6.

FIGURE 10 is a fragmentary cross sectional view taken substantiallyalong the plane indicated by the line 10-10 of FIGURE 9 and alsoillustrating in phantom the manner in which the truss is adapted to belocated with respect to the casting bed when carrying out the method ofthe instant invention.

FIGURE 11 is a top plan view similar to FIGURE 1 but showing the hoppercarriage moved along the casting bed and a first truss member disposedwithin the casting bed.

FIGURE 12 is a fragmentary cross sectional view taken substantiallyalong the plane indicated by the line 1212 of FIGURE 11.

FIGURE 13 is an enlarged detail of the lefthand portion of FIGURE 12indicated by the circle 13.

FIGURE 14 is a fragmentary cross sectional view taken substantiallyalong the plane indicated by the line 1414 of FIGURE 12 and showing inphantom the location of a second truss element on the casting bed withrespect to a first truss element.

FIGURE 15 is a top plan view as seen substantially along the planeindicated by the line 15-15 of FIG- URE 14.

FIGURE 16 is an end view in elevation illustrating the manner in which apair of identical truss decks formed by the apparatus and method of thepresent invention can be joined to each other in constructing a roof orfloor.

FIGURE 17 is an enlarged detail view, partly in section, of the centralportion of FIGURE 16 indicated by the circle 17.

The apparatus of the instant invention includes a casting bed generallydesignated by the numeral 20.

The casting bed 241 includes a floor 21. The floor 21 is mounted on thetop flanges of a pair of parallel I-beams 40 and 44 running the lengthof the casting bed. Mounted between the opposed webs of the I-beams 40,44 adjacent their ends, are a pair of parallel, rectangular beams 41 and42. The I-beams 4t) and 44 are supported by transverse beams 23 and 24at their respective ends.

A side wall 48 is pivotally connected to the web of the I-beam 40.Similarly, a side Wall 50 is pivotally connected to an I-beam 44. Sidewalls 48 and 50 extend the longitudinal length of the I-beams.

The side walls 48 and 50 include a plurality of longitudinally spacedtriangular shaped brackets 60. Secured to the webs of the I-beams 46 and44 are a plurality of pairs of triangularly shaped brackets 62. Each ofthe brackets 60, 62 include a hinge collar 64. The hinge collar on thebracket 60 is disposed between the hinge collars on a pair of brackets62 and a hinge pin is inserted within the collars.

End walls 46 and 52 are supported at remote ends of the casting bed 20upon the top flanges of the I-beams 40 and 44. The end walls 46 and 52are pivotally mounted to the rectangular beams 42 and 41 respectively. Aplubrackets 54 are disposed between a pair of adjacent hinge collar 58are secured to the end walls 46 and 52. Pairs of spaced triangularbrackets 56 are secured to the rectangular beams 42 and 41. The brackets56 also terminate in a hinge collar 58. The hinge collars on thebrackets 54 are disposed betwen a pair of adjacent hinge collars on thebrackets 56 an a pivot pin is run through the aligned collars.

A pair of rails 26 and 28 are supported on top of the transverse beams23 and 24 and run the length of the casting bed 20. Mounted on the rails26 and 28 in overlying relation to the casting bed floor 21 is a hopper22 for dispensing cementitious material. The hopper 22 includes aplurality of wheels 30 in enga ement with the 32, as shown in FIGURE 2,about which is entrained an endless chain 38. A bracket 34 extends incantilever fashion from the side of the hopper 22. An electric motor 36is supported upon the bracket 34. A sprocket is mounted upon the motorshaft and engages the endless chain 38. Therefore, upon actuation of theelectric motor 36, the wheels 30 of the hopper 22 will be rotated andthe hopper can be caused to selectively move along the casting bed 20.

In the fabrication of the truss deck by the method of the instantinvention, a preassembled truss 66 is provided. The truss 66 includes apair of spaced, substantially parallel joist sections 68 and 70. Thejoist sections 68 and 70 are connected by a steel joist web 72. Theouter portions of the joist web 72 are inclined away from the bottomchord of the joists 68 and 70.

The top chord 74 of each joist section includes a pair of slopingextensions 76 and 82 at its opposite ends. The extensions 76 and 82terminate in horizontal portions 78 and 84 respectively. The horizontalportion 78 includes an aperture 80. Similarly, the horizontal extension84 includes an aperture 86.

Removably secured to the horizontal extension portion 78 is an angleiron positioning bar 88. Core pins 90 connect the positioning bar 88 tothe horizontal extension 78 by being inserted within the apertures 80.

A Z-shaped cut-off bar 92 is removably supported upon the horizontalextensions 84. Core pins 94 attached to the cut-off bar 92 are insertedin the apertures 86 in the horizontal extensions 84.

As shown in FIGURES l2 and 13, a continuous upstanding flange 98 isprovided along the opposite longitudinal edges of the floor 21 of thecasting bed 20.

The method of the present invention is carried out with the previouslydescribed apparatus, substantially as follows:

The side and end walls of the casting bed are disposed in their upperpositions to close the casting bed. A light oil film is applied to theinside flanges of the side walls 48 and 50 and the end walls 46 and 52of the casting bed 20. The oil film is also applied on the floor 21 ofthe casting bed.

The motor 36 is actuated to cause movement of the hopper 22 along therails 26 and 28. As the hopper 22 moves along the casting bed above thefloor 21, cementitious material is dispensed through a door in thebottom of the hopper onto the floor 21 of the bed 20.

As soon as the hopper 22 reaches a position as substantially shown inFIGURE 11, the truss 66 is immersed within the cementitious material 96deposited on the bed 21. The truss 66 is lowered into the cementitiousmaterial 96. An oil film is applied to the positioning bar flanges andthe cut-off bar flanges. The truss 66 is vibrated by means of jackhammers or the like as it is immersed.

As shown in FIGURES 11-15, the positioning bar 88 is lowered until itshorizontal flange seats upon the side walls 48 and 50 and the edge ofthe horizontal flange abuts the upstanding flange on the end wall 46.The cutoff bar 92 is lowered until the bottom edge of one of itsvertically extending flanges seats on the side walls 48 and 50 and itsother vertically extending flange seats on the floor 21 of the bed 20.The lateral dimension of the floor 21 is such that the angularlyextending portions of the joist web 72 are seated between the upstandingflanges 98 on the floor 21.

The core pins supported by bar 88 and bar 92 are also dimensioned toseat upon the floor 21 of the casting bed.

Meanwhile, the hopper 22 is continuing its travel along the casting bed20. More cementitious material 96 is deposited upon the floor 21. Assoon as space allows, a second truss 66 is immersed within thecementitious material 96. The positioning bar 88 on the second immersedtruss is seated upon the opposed side walls 48 and 50. An edge of thehorizontal flange of the positioning bar 88 is placed in abutment withthe horizontal flange of the cut- 4 off bar 92 on the previouslyimmersed truss. shown in phantom in FIGURES l4 and 15.

The process is continued as previously described until the casting bed20 is filled and a desired number of trusses 66 have been immersed. Inpractice, the casting bed is approximately 80 feet in length.

The cementitious mixture is then allowed to harden. The hopper 22 isremoved from the tracks 26 and 28. Side walls 48 and 50 are then pivotedaway from the hardened mixture on the floor 21. The end walls 46 and 52are also pivoted away from the hardened mixture.

The individual trusses 56 and cementitious material attached thereto maythen be elevated from the floor 21 of the casting bed 20. A plurality oftruss desks have been formed because of the plurality of chambersdefined by the cut-off bars 92 when they were disposed within thecementitious material 96. The resultant truss deck is inverted andsupported upon the chords 74. The truss decks may be stacked one on topof each other for ready transportation or storage at the constructionsite.

Each truss deck includes the open web steel joist sections 68 and 70 anda concrete slab reinforced by the joist web 72. Due to the inclusion ofthe upstanding flanges 98 on the floor 21 of the casting bed,longitudinally extending notches 101 are formed along the opposedlongitudinal edges of the slab. As shown in FIGURE 17, the ends of thejoist web 72 are exposed by the notches 101.

The last mentioned construction lends itself to easy assemblage of thetruss decks at the construction site.

As shown in FIGURE 16, the inverted truss decks are adapted to havetheir longitudinal edges placed in abutment to form a roof or floor atthe construction site. The juxtaposed notches 101 form a longitudinalopening 100. The exposed ends of the joist web may be Welded together asshown at 102. Hence, each truss deck may be easily joined to another atthe construction site to form a prefabricated floor or roof element.

Removal of the core pins 94 from the hardened mixture results in theformation of a plurality of anchor holes. The prefabricated roof orfloor can then be secured to other structural components of, thebuilding.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

1 claim:

1. A method of fabricating building slabs comprising the steps ofpouring a cementitious mixture into a casting bed substantially longerthan the desired length of a slab, providing a preassembled reinforcedtruss of a length less than the length of the casting bed and having twospaced susbtantially parallel joists, immersing a portion of said trussinto a portion of said mixture with the major portion of the joistsabove and spaced from the mixture, immersing a cut-off bar into saidmixture to separate said portion from the remainder of said mixture,vibrating said truss while it is immersed in said mixture, providing asecond pre-assem bled reinforced truss having two spaced substantiallyparallel joists, immersing a portion of said second truss into theremainder of said mixture, vibrating said truss while it is immersed insaid mixture; permitting said mixture to solidify into slabs integralwith said trusses, separating the trusses and their solidified slabsfrom said bed and cutoff bar, and then turning said slabs and trussesover so that the slabs are supported by the trusses.

2. A method in accordance with claim 1 including using a casting bedhaving a longitudinally extending protrusion along the side edges of itsfloor, immersing said trusses so that portions on the trusses abut saidprotrusions, so that the solidified slabs will have a notch at the uppercorner along their lengths exposing the said portions of the trusses.

3. A method in accordance with claim 1 including providing at least onecore pin on at least one end of one of This is said trusses with the pinextending to the floor of the bed, and removing said pin after themixture has solidified into slabs and the sla'bs have been separatedfrom the bed, thereby providing an anchor hole adjacent an end of theslab.

4. A method in accordance with claim 11 wherein said preassembledreinforced truss of a length less than the length of the casting bed andhaving two spaced substantially parallel joists has the cutoff barconnected thereto at one end, including immersing said preassembledrein- 10 References (Iited by the Examiner UNITED STATES PATENTS2,705,886 4/ 1955 Annett 52723 2,948,947 8/ 1960 Berg et a1 264422,979,801 4/1961 Gasmire 264-42 3,173,193 3/1965 Grebner et al. 29155ROBERT F. WHITE, Primary Examiner. ALEXANDER H. BRODMERKEL, Examiner. I.A. FINLAYSON, Assistant Examiner.

1. A METHOF FABRICATING BUILDING SLABS COMPRISING THE STEPS OF POURING ACEMENTITIOUS MIXTURE INTO A CASTING BED SUBSTANTIALLY LONGER THAN THEDESIRED LENGTH OF A SLAB, PROVIDING A PREASSEMBLED REINFORCED TRUSS OF ALENGTH LESS THAN THE LENGTH OF THE CASTING BED AND HAVING TWO SPACEDSUBSTANTIALLY PARALLEL JOISTS, IMMERSING A PORTION OF SAID TRUSS INTO APORTION OF SAID MIXTURE WITH THE MAJOR PORTION OF THE JOISTS ABOVE ANDSPACED FROM THE MIXTURE, IMMERSING A CUT-OFF BAR INTO SAID MIXTURE TOSEPARATE SAID PORTION FROM THE REMAINDER OF SAID MIXTURE, VIBRATING SAIDTRUSS WHILE IT IS IMMERSED IN SAID MIXTURE, PROVIDING A SECONDPRE-ASSEMBLED REINFORCED TRUSS HAVING TWO SPACED SUBSTANTIALLY PARALLELJOIST, IMMERSING PORTION OF SAID SECOND TRUSS INTO THE REMAINDER OF SAIDMIXTURE, VIBRATING SAID TRUSS WHILE IT IS IMMERSED IN SAID MIXTURE;PERMITTING SAID MIXTURE TO SOLIDIFY INTO SLABS INTEGRAL WITH SAIDTRUSSES, SEPARATING THE TRUSSES AND THEIR SOLIDIFIED SLABS FROM SAID BEDAND CUTOFF BAR, AND THEN TURNING SAID SLABS AND TRUSSES OVER TO THAT THESLABS ARE SUPPORTED BY THE TRUSSES.